The traditional fluorescent lamp comprises ballast and starter to start and drive the fluorescent lamp for its illumination. However, the structure of such conventional lamps seems complex. Their volume are large. They always cost higher power consumption and longer starting time.
Mr. John T. Pierce disclosed a "Power source for fluorescent lamps and the like" patented on June 10, 1975 (U.S. Pat. No. 3,889,153) to have improved light output, lower power consumption and high reliability for fluorescent lamps. However, the lamps are independently separated with the oscillator circuit so that several capacitors are provided to couple the electric energy from the oscillating power source with the lamps. Hence, several defects are found as follows:
1. Several windings of the transformer must be provided to induce voltage to pre-heat the lamp filaments to cause dissipation of electric energy. PA1 2. Whenever removing either lamp from the circuit, an open circuit will occur so that the voltage across the transformer primary winding will be increased during the transistor turn-off portion of the inverter cycle. The increased voltage may cause overheating of the transistors or serious damage to the capacitors. Hence, a unique protective circuit must be further provided to increase the product cost. PA1 3. As high voltage oscillation, the high tension will still exist on both sides of lamp sockets to cause danger when removing the lamp tube. PA1 4. The oscillator circuit is independently separated with lamps so that it will consume energy in despite of the connection or disconnection of fluorescent lamps.
The present inventors have found the defects and researched to disclose the present simplified power source for fluorescent lamps.